I think you're missing the point that it's fundamentally un-Apple-like to have two new products that out-of-the-box can't connect with each other.

That might be OP's point, but that ignores the fact that Apple would likely dealing with a much worse PR disaster when millions of users can't plug their phone into literally anything they own without first buying a USB-A cable.

Seems like you don't know apple. They have always favored fancy features and out of box experience with other apple products over out of the box backwards compatibility.

It's really not usual at all especially for devices that are not required to be connected to each other or span different generations of Macs.

The AirPort has never come with an Ethernet cable

The iPod never shipped with both FireWire and USB to 30 pin cables

The ThunderBolt Display was incompatible with Macs without ThunderBolt ports

The 30" Cinema display was only compatible with the Mac Pro when it launched and later required adapters (not included) to be used on other Macs

The original iPhone's recessed headphone jack required an adapter to use older iPod headphones

The first generation of Apple USB mice/keyboards did not come with an ADB adapter

Why can't Apple ship both a USB-A and USB-C cable? In the early 2000s, Apple bundled both a USB and a Firewire cable in the packaging with a new iPod, presumably to facilitate exactly the sort of transition they're confronting now.